I scratched my head over that one too…(although in 4.1.2 factory rather than 4.2 in unstable) thought it was lithium first, but no. Turned out you need to uninstall powersaved. In other words, it is not a KDE power manager that has been detected but a general powersave daemon.
Unfortunately, removing powersaved necessitates removing smartmontools as well but if you feel you can live without that it is of little concern.
I found out that in fact you do not have to remove the powersave daemon (the smarttools dependence) all you have to do is to stop the daemon from the services.